1. Field of the Invention.
The present invention relates to beds generally and, more particularly, to a novel bed structure especially suited for low air loss air beds and being exceptionally economical to manufacture and use.
2. Background Art.
While the present invention and particular features thereof are described for illustrative purposes as being applied, in one embodiment, to low loss air beds, it will be understood that the various aspects of the invention have applications in other types of beds, as well as in non-bed applications, and all such applications are within the intent of the present invention.
A major problem in health care facilities is with bed-bound patients who cannot turn or roll over without assistance. Failure to roll over relatively frequently causes restriction of blood flow in the area of bony protuberances on a patient's body which, in turn, causes ulcerated bed, or pressure, sores. Such sores are extremely long-healing and, with a chronically or terminally ill patient, frequently recur. According to hospital industry standards, it has been estimated that to cure a single bed sore costs society an average $40,000 and many patients die from bed sores. A standard procedure is to have nursing personnel turn each immobile patient every two hours. This is not entirely unsatisfactory in a hospital setting where nursing staff is continually available, but may be an unsatisfactory procedure in institutions, such as nursing homes, or in private homes where such assistance may not be available on a frequent basis. One conventional technique for avoiding bed sores is to have the patient repose in a plaster of Paris bed in which the plaster of Paris has set to the patients contours. Although providing a hard surface, there is sufficient surface area that the pressure on the patient's body remains below the body's capillary pressure.
A recent development to address the problem of bed sores is the so-called "low loss air bed". This type of bed comprises a fairly typical hospital bed which has, instead of a standard mattress, a plurality of air bags disposed perpendicularly to the axis of the bed from its head to its foot. The shape of the air bags permits their deformation to accommodate the contours of the patient's body without undue local pressure areas developing. The pressure within the air bags is adjusted to give just the required support to each portion of the patient's body and the adjustment can be changed to periodically vary the pressure on each or all portions for eating, sleeping, etc. Such use of air bags greatly reduces the tendency for bed sores to form and, indeed, can promote the healing of already formed bed sores. Typically, small streams of air are ejected from the upper sections of the air bags which are covered by a vapor-permeable sheet, such as a microporous polyurethane-coated nylon fabric. The streams of air dry any moisture vapor which permeates through the sheet and, therefore, helps remove another cause of bed sores and reduces the frequency of bedding changes. A discussion of the formation and prevention of bed sores, as well as some conventional types of low loss air beds may be found in Bed Sore Biomechanics, edited by R. M. Kenedi, J. M. Cowden, and J. T. Scales, Macmillan Press Ltd. publisher, 1976, which book and the references cited therein are made a part hereof by reference.
Conventional air beds typically include features found on standard hospital beds such as means to raise or lower head and/or foot portions, means to adjust the height of the bed, etc. Frequently, such air beds consume a relatively large volume of air, thus requiring a relatively large blower and creating a noise problem from the air flow and the controls therefor unless extraordinary measures are taken to dampen the noise. It would be desirable to have an air bed having low air flow requirements and having air flow control components which inherently produce a low noise level.
Perhaps the greatest disadvantage with conventional air beds is that of high manufacturing cost. Such beds are fabricated from numerous small parts manually attached with fasteners and complex weldments and having a high labor content. Also, some of the features which are included in standard hospital beds contribute to the high cost. The result of the high cost is that the use of such beds is restricted almost entirely to hospitals that have the financial means to purchase or rent such beds and, thus, immobile patients who otherwise could be discharged to a nursing home or private home must be maintained in the formal hospital setting. It would be highly desirable to have available an air bed which could be afforded by those outside of a formal hospital setting.
Another class of persons subject to pressure sores are those who are handicapped and working, but who are confined to wheelchairs. The day-long confinement to a wheelchair causes the same problem with pressures sores as does confinement in a bed. In such a situation, when the person develops one or more such sores, the person must drop out of the person's position in society for a month or more while the sore is cured. Of course, when the person returns to the wheelchair, sores will likely recur and the process is repeated. It has been found that, if such a person is able to sleep in an air bed, such permits incipient sores to heal during the night, even though the person is confined to a wheelchair during the day. Unfortunately, the cost of a conventional air bed puts it out of the reach of many such persons who must continue to suffer.
A further factor contributing to the relatively high cost of conventional air beds is the arrangement of the air bags. Typically, the bags are arranged in groups of three to five bags each with the bags in a group supplied with air of the same pressure through a manifold. It would be simpler to have a single air bag approximating the dimensions of three or more conventional air bags, but simply making one bag larger would cause that bag to approach a spherical shape, thus making it unsuitable for patient support. However, it would be desirable to have available a single air bag which would simulate a group of conventional air bags. Such a single bag would simplify the air supply arrangement and be more economical to manufacture.
An important cost factor in the use of conventional air beds is their lack of portability. This means that shipping and installing such beds requires a relatively costly procedure and, of course, it is impossible for an ambulatory or wheelchair bound patient requiring an air bed to conveniently relocate, or have relocated, such a bed. It would be desirable to have a device with the therapeutic features of an air bed, but one that is highly portable and can easily be shipped by conventional mail or by commercial parcel delivery services and which can be easily relocated.
Another feature of standard hospital-type beds that can contribute to their high cost, and also that contributes to difficulty in their use by the patient or the patient's aide, is the siderails employed with such beds. Typically, such siderails are of one of two types. One type comprises a single-piece tubular siderail structure which extends substantially the length of the bed and which must be lifted off to allow the patient to be moved or, if the patient is mobile, to allow the patient to exit or enter the bed. Removal and replacement can be difficult for the aide and impossible for the impatient. The other typical type comprises a similar siderail structure which has a complicated and expensive hinged mechanism to allow the siderail to be lowered to the floor. This may be more convenient for the aide, but is impossible for the patient to maneuver if the patient is in the bed.
Accordingly, it is a principal object of the present invention to provide a bed structure which is simple and economical to manufacture and which may be used in a number of applications, including air beds.
A further object of the invention is to provide a air bed which is simple and economical to manufacture and which may be used in nursing homes or private homes.
Another object of the invention is to provide an air flow control valve which inherently produces a low level of noise, which is economical to manufacture, and which may be used for air flow control on air beds.
An additional object of the invention is to provide a single air bag which simulates a plurality of conventional air bags and which may be used for air beds.
Yet an additional object of the invention is to provide a bed siderail which is relatively economical and which is easy to manipulate either by the patient unattended or the patient's aide.
Yet another object of the invention is to provide a device offering the features of an air bed, but one which is highly portable and may be shipped by conventional mail or by commercial parcel delivery services.
Other objects of the invention, as well as particular features and advantages thereof, will, in part, be obvious and will, in part, be apparent from the following description and the accompanying drawing figures.